Ok, update time.......
So after 2x dyno sessions and 6x track days (a total of approx 200km of driving - if that) the standard EVO2 5th gear was destroyed towards the end of the front straight at Winton.
This resulted in having to pull the gearbox out and apart to determine the extent of the damage. Fortunately the shrapnel from the 5th gear had not made its way through the gearbox, but the inspection uncovered something else that was very unexpected and extremely disappointing.
I've been asked for feedback on my upgraded EVO2 gearbox, so here it is.
The attached images are of the straight cut 3rd and 4th gears that I purchased. Every tooth is showing signs of pitting and wear and we suspect it's an issue with the hardness of the material used. This gearbox was run on Redline MT 75W90 gear oil as recommended and has seen no more than 200km of use, but these gears look like they have come out of a car that has done 200,000+ km.
I had already replaced this gearbox with a PPG dogbox so I was not relying on having to put this one back in the car to keep driving, but unfortunately I was hoping to sell it, to off-set some of the cash spent on the PPG.
Neither Andrew (of CVAP) or myself are comfortable with putting these gears back in the gearbox, bolting it together and selling it to the "next poor sucker" to make it their problem - that's "just NOT cricket!"
I've been offered replacement gears at a cost of approx $1200AUD (not including shipping) but cannot justify spending this kind of $$$, plus what it will cost to rebuild the gearbox, to then sell it and walk away with (hopefully) enough to cover what it cost me just to rebuild it a 2nd time!!
Not a "Happy-Chappy" at the moment.